Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,299   Posts: 1,535,743   Online: 816
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 19
  1. #1

    Join Date
    Nov 2006
    Location
    Luxembourg
    Shooter
    Multi Format
    Posts
    93
    Images
    5

    Schneider-K. Componon-S 50mm enlarger lens - sharp??

    a test I made today shows that this lens gets sharper for each stop down, from 2.8 to 16. At 2.8 it's not sharp at all, at 8 it's acceptable but there is still a substantial improvement by going down to 16. This seems to be contrary to what Schneider and most people say.
    I think my method of testing was robust, enlarger head raised to ca. 10x enlarging, focused on the grain, used one single pin sharp neg (135), did'nt move the easel. My enlarger : Durst M670 VC.
    I should be grateful if anybody can comment or help to explain what I'm getting wrong. It's a pain if I always have to use f16 to get my images sharp.Thanks in advance
    Peter

  2. #2
    ath
    ath is offline
    ath's Avatar
    Join Date
    Aug 2006
    Location
    Germany
    Shooter
    35mm
    Posts
    890
    Did you focus with a red filter between lens and negative?
    Regards,
    Andreas

  3. #3

    Join Date
    Apr 2008
    Location
    Chicago
    Shooter
    35mm
    Posts
    106
    Try it again, but focus at the same lens opening you will be using for the exposure.

  4. #4
    Newt_on_Swings's Avatar
    Join Date
    Mar 2011
    Location
    NYC
    Shooter
    Multi Format
    Posts
    1,814
    What type of grain finder are you using? and did you focus that correctly before you started to use it under the enlarger?

    If you are not using the grain finder correctly, all your prints will not be sharp, and you would have to rely on stopping it way down. Once you get too small diffraction starts to kick in and from then on it will not be as sharp either.

    And as well as including what the previous posts have said, I have read that in the past enlarger lenses had quite a bit of variation between each other in sharpness even from the same line and manufacturer. There is a old popphoto article on it somewhere and I think it was common at one time for a printer to buy a few copies of the same enlarger lens and choose the best, and return the rest.

  5. #5
    ic-racer's Avatar
    Join Date
    Feb 2007
    Location
    Midwest USA
    Shooter
    Multi Format
    Posts
    6,182
    This is what you should be seeing with a grain magnifiier if all is OK with your system:

    At 2.8 at the center, grain is sharp but low in contrast. Edges my not be so sharp
    As you stop down contrast increases but sharpness decreases with each stop.
    At f8 you have a good compromise between diffraction and edge sharpness
    Past f8 it gets mushy and the grain gets indistinct.

  6. #6
    Rol_Lei Nut's Avatar
    Join Date
    Jul 2006
    Location
    Hamburg
    Shooter
    Multi Format
    Posts
    1,118
    My own experience with that lens: usable at f/2.8 (corner grain not perfect), but used it more often at 5.6 or 8.0 to offset any focusing or enlarger-paper geometric imperfections.
    The older 4.0 Componon might have a touch more acutance at those stops, but the "S" is certainly no slouch!

    As others suggested, check your technique.
    Maybe shake the lens next to your ear to hear if there are any loose elements inside...
    M6, SL, SL2, R5, P6x7, SL3003, SL35-E, F, F2, FM, FE-2, Varex IIa

  7. #7
    Ian Grant's Avatar
    Join Date
    Aug 2004
    Location
    West Midlands, UK, and Turkey
    Shooter
    Multi Format
    Posts
    16,246
    Images
    148
    Make 100% certain your Durst isn't creeping. Both the head on the column and the lens focussing wear over time and can slip, the head can actually creep up the column. There's pressure pads that prevent this and after a time they need a slight tightening.

    Ian

  8. #8
    sandermarijn's Avatar
    Join Date
    Oct 2005
    Location
    Leiden, Netherlands
    Shooter
    35mm
    Posts
    771
    Images
    11
    My M670 had focus creep. The seller fixed it.

  9. #9

    Join Date
    Nov 2006
    Location
    Luxembourg
    Shooter
    Multi Format
    Posts
    93
    Images
    5
    thank you to everybody for your help!
    to Andreas : no, there is nothing to disturb between neg and lens!
    And yes, it's possible that my focusing on grain is the problem. Have three focus finders: Paterson major and minor and LPL . I prefer LPL because its bigger enlargement.
    Tomorrow I'll return to darkroom and re-test. I also have a Nikon EL 50mm to compare with (not done so far).
    Ian and Sandermarijn: pretty sure there is no creeping going on, that was first thing I checked. But the Durst is not that easy to adjust finely.
    I'll report back after next tests.
    Peter

  10. #10
    sandermarijn's Avatar
    Join Date
    Oct 2005
    Location
    Leiden, Netherlands
    Shooter
    35mm
    Posts
    771
    Images
    11
    I think I still have a 50mm/2.8 Rodagon lying around unused. Will have to check tomorrow or the day after. If I can find it and if it looks decent enough you can have it if you like. Just for making things even more confusing ;-)

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin